Rapid Pathogen Detection by Surface Swab Sampling and Wireless Biosensing

Wednesday, 4 October 2017
National Harbor 10 (Gaylord National Resort and Convention Center)
Y. Liu, S. Du (Materials Research & Education Center, Auburn University), S. Horikawa (Auburn University), I. H. Chen, J. Xi (Material Research & Education Center, Auburn University), T. S. Huang (Auburn University), and B. A. Chin (Material Research & Education Center, Auburn University)
This paper presents a method that combines surface swab sampling and wireless biosensing for rapid detection of foodborne pathogens on solid surfaces. The method can be applied to any surfaces, including the surface of food processing tables and fresh produce, for improving food safety. Surface swab sampling is an inexpensive and easy-to-use method of collecting pathogens. A desired area or the whole area of a target surface (if needed) can be swabbed to collect pathogens rapidly. In this study, we first investigated the efficiency of capture and release of a model pathogen, Salmonella Typhimurium, in swab sampling. A Salmonella-contaminated surface (2 × 2 cm2 flat polyethylene slab) was prepared by using a spot-inoculation method. Five drops of a Salmonella solution (20 ul/drop at concentrations from 5X108 cfu/ml to 5X103 cfu/ml) were inoculated on the polyethylene surface and allowed to dry in a biosafety cabinet for 2 hours. Swab sampling was then conducted at a controlled temperature and humidity to capture the pathogen. Finally, the swabs used were dipped in a TBS solution for releasing the captured Salmonella cells. Various swab tip materials were tested, including cotton, rayon, and nylon. The effects of swab force and sonication/vortexing on the capture and release efficiency were also investigated. The released Salmonella cells were finally detected and quantified instantaneously by using a wireless phage-based magnetoelastic biosensor. By comparing the quantities of the initially inoculated cells and detected cells, the efficiency of capture and release was calculated.